<html>
<head>
	<meta charset="UTF-8">
	<meta content="IE=edge" http-equiv="X-UA-Compatible">
	<meta content="initial-scale=1.0, maximum-scale=1.0, user-scalable=no, width=device-width" name="viewport">
	<title>2455：TopCoder MSRM 485 Deposit</title>
	<!-- css -->
	<link href="../css/base.min.css" rel="stylesheet">
	<link href="../css/project.min.css" rel="stylesheet">
	
	<!-- favicon -->
	<!-- ... -->
</head>
<body class="page-brand">
	<header class="header header-transparent header-waterfall ui-header">
		<ul class="nav nav-list pull-left">
			<li>
				<a data-toggle="menu" href="#menu">
					<span class="icon icon-lg">menu</span>
				</a>
			</li>
		</ul>
		<a class="header-logo header-affix-hide margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">TopCoder MSRM 485 Deposit</a>
		<span class="header-logo header-affix margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">TopCoder MSRM 485 Deposit</span>
	</header>
	<nav aria-hidden="true" class="menu" id="menu" tabindex="-1">
		<div class="menu-scroll">
			<div class="menu-content">
				<a class="menu-logo" href="../index.html">BZOJ离线题库</a>
				<ul class="nav">
					<li>
						<a class="waves-attach" data-toggle="collapse" href="#problems">题目</a>
						<ul class="menu-collapse collapse in" id="problems">
							<li>
								<a class="waves-attach" href="../index.html">主页</a>
							</li>
							<li>
								<a class="waves-attach" href="../list.html">题目列表</a>
							</li>
						</ul>
					</li>
					<li>
						<a class="collapsed waves-attach" data-toggle="collapse" href="#about">关于</a>
						<ul class="menu-collapse collapse" id="about">
							<li>
								<a class="waves-attach" href="../about.html">关于此项目</a>
							</li>
						</ul>
					</li>
					
				</ul>
			</div>
		</div>
	</nav>
	<main class="content">
		<div class="content-header ui-content-header">
			<div class="container">
				<h1 class="content-heading">
                TopCoder MSRM 485 Deposit                </h1>
                <p>时间限制：5s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
		</div>
		<div class="container">
			<section class="content-inner margin-top-no">
				<div class="row">
					<div class="col-lg-13 col-md-13">
						<div class="card margin-bottom-no">
							<div class="card-main">
								<div class="card-inner">
									
                                <h3>题目描述</h3><p><p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: '宋体'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt">从前，森林里有一只脑子进水的兔子。</span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: 'Times New Roman'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: '宋体'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt">它平时搞<font face="Times New Roman">OI</font><font face="宋体">，做题做累了就开始在森林里探险。</font></span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: '宋体'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt">兔子的探险在森林里进行，森林可以视为一个凸多边形区域。森林中，有一块同样为凸多边形的宝地，种满了萝卜！！！</span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: '宋体'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt">兔子的游戏很哲学，游戏过程是这样的，兔子从森林的边缘随机选一个起点，然后选择森林边缘上离起点最远的点做终点（如果有多个点，那么等概率选择其中一个），兔子会从起点开始，沿直线一路跑到终点，如果奔跑的过程中，它路过了萝卜地，那么兔子觉得这个起点是一个幸运点，否则，兔子认为这个起点是没有意义的。现在兔子想知道，它选到幸运点的概率是多少。</span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; position: relative; top: 3pt; mso-spacerun: 'yes'; mso-text-raise: -3.0000pt"><o:p></o:p></span></p>
<!--EndFragment--></p><hr/><h3>输入格式</h3><p><p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; margin-left: -26.25pt; text-indent: 26.25pt"><span style="font-size: 10.5pt; font-family: '宋体'; mso-spacerun: 'yes'">输入文件第一行包含两个整数<font face="Times New Roman">N</font><font face="宋体">和</font><font face="Times New Roman">M</font><font face="宋体">，表示森林边缘的点数和萝卜地边缘的点数。</font></span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; margin-left: -26.25pt; text-indent: 26.25pt"><span style="font-size: 10.5pt; font-family: '宋体'; mso-spacerun: 'yes'">第二行和第三行，以逆时针顺序给出森林。第二行<font face="Times New Roman">N</font><font face="宋体">个整数，表示</font><font face="Times New Roman">N</font><font face="宋体">点的</font><font face="Times New Roman">x</font><font face="宋体">坐标，第三行给出</font><font face="Times New Roman">N</font><font face="宋体">个相应的</font><font face="Times New Roman">y</font><font face="宋体">坐标。</font></span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; margin-left: -26.25pt; text-indent: 26.25pt"><span style="font-size: 10.5pt; font-family: '宋体'; mso-spacerun: 'yes'">第四行和第五行，以逆时针顺序给出萝卜地。第四行<font face="Times New Roman">M</font><font face="宋体">个整数，表示</font><font face="Times New Roman">M</font><font face="宋体">个点的</font><font face="Times New Roman">x</font><font face="宋体">坐标，第五行给出</font><font face="Times New Roman">M</font><font face="宋体">个相应的</font><font face="Times New Roman">y</font><font face="宋体">坐标。</font></span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<!--EndFragment--></p><hr/><h3>输出格式</h3><p><p class="p0" style="margin-top: 0pt; margin-bottom: 0pt; text-indent: 21pt"><span style="font-size: 10.5pt; font-family: '宋体'; mso-spacerun: 'yes'">输出文件仅包含一个数，既兔子取到幸运点的概率，四舍五入保留<font face="Times New Roman">9</font><font face="宋体">位小数。</font></span><span style="font-size: 10.5pt; font-family: 'Times New Roman'; mso-spacerun: 'yes'"><o:p></o:p></span></p>
<!--EndFragment--></p><hr/><h3>样例输入</h3><pre>4 4
0 4 4 0
0 0 4 4
1 2 2 1
1 1 2 2
</pre><hr/><h3>样例输出</h3><pre>0.666666667
</pre><hr/><h3>提示</h3><p><p>&nbsp;对于100%的数据，有3 &le; N,M &le; 50。坐标绝对值不超过1000。</p></p><hr/><h3>题目来源</h3><p>2011福建集训</p>
								</div>
							</div>
						</div>
					</div>
				</div>
				
				
			</section>
		</div>
	</main>

	<div class="fbtn-container">
		<div class="fbtn-inner">
			<a class="fbtn fbtn-lg fbtn-brand-accent waves-attach waves-circle waves-light waves-effect" data-toggle="dropdown" aria-expanded="true"><span class="fbtn-text fbtn-text-left">Menu</span><span class="fbtn-ori icon">apps</span><span class="fbtn-sub icon">close</span></a>
			<div class="fbtn-dropup">
				<a class="fbtn fbtn-brand waves-attach waves-circle waves-light waves-effect" href="../list.html" target="_self"><span class="fbtn-text fbtn-text-left">题目列表</span><span class="icon">menu</span></a>
				<a class="fbtn fbtn-green waves-attach waves-circle waves-effect" href="../index.html" target="_self"><span class="fbtn-text fbtn-text-left">返回主页</span><span class="icon">home</span></a>
				<a class="fbtn waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=2455" target="_blank"><span class="fbtn-text fbtn-text-left">提交代码</span><span class="icon">send</span></a>
				<a class="fbtn fbtn-orange waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/wttl/wttl.php?pid=2455" target="_blank"><span class="fbtn-text fbtn-text-left">试题讨论</span><span class="icon">chat</span></a>
				
			</div>
		</div>
	</div>

	<!-- js -->
	<script src="../js/jquery.min.js"></script>
	<script src="../js/base.min.js"></script>
	<script src="../js/project.min.js"></script>
</body>
</html>